Nowadays, thin film transistor (TFT) LCDs (TFT-LCDs) have become a kind of important displaying platforms in modern IT products and video products. A TFT-LCD generally comprises an array substrate and a color filter (CF) substrate disposed opposite to each other as well as a liquid crystal material sandwiched between the array substrate and the CF substrate. The TFT-LCD operates mainly in the following principles: liquid crystal molecules can twist under the action of a voltage applied across the liquid crystal material between the array substrate and the CF substrate, and different light transmissivity values can be obtained by applying different voltage levels, thus achieving the purpose of displaying.
Currently, the array substrate and the CF substrate are usually assembled together through adhesion by means of a sealant, and electric signals from the CF substrate are connected to circuits on the array substrate primarily via Au balls having a radius on the order of micrometers.
In the manufacturing process of an LCD panel, usually a mother substrate of a large size is sliced into a plurality of substrates. In this process, the array substrate and the CF substrate need to be assembled together through use of the sealant. Currently, a primary sealant, a secondary sealant and a conductive medium have to be applied to the array substrate and the CF substrate. The primary sealant, which is disposed outside the displaying region, is mainly used to assemble the array substrate and the CF substrate together. The secondary sealant is mainly used to protect the array substrate and the CF substrate when they are assembled together, and will be removed when the mother substrate is sliced into substrates. The conductive medium is applied on a route of a primary frame and is usually applied during or after the process of applying the primary sealant and the secondary sealant.
Currently, there are mainly two kinds of approaches of applying the sealants and the conductive medium. The first kind of approach is to firstly apply the primary sealant and the secondary sealant and finally the conductive medium is applied; and the second kind of approach is to mix the primary sealant with the conductive medium, then apply the primary sealant and the conductive medium in a single step, and finally the secondary sealant is applied.
However, the two kinds of approaches described above have the following main problems: firstly, both the first kind of approach and the second kind of approach require at least two applying steps, which consume a long time; and secondly, the second kind of approach which mixes all the conductive medium into the primary sealant consumes a significantly increased amount of the conductive medium, so the material cost is increased, and meanwhile, because the conductive medium is also applied unnecessarily to sites of signal lines, the probability of defective products is increased and quality of the products is degraded.